Plastic is a popular material used to make bottles that are both transparent and shatter resistant. Typically, sports bottles and baby bottles are placed in the dishwasher at some point and are subjected to high temperatures and to chemical exposure. Thus, plastics with higher Tg values, such as bisphenol-A polycarbonate, amorphous polyamide and polysulfone, are commonly used to fabricate sports bottles or baby bottles.
Many plastic bottles are produced by blow molding, which restricts the materials to high Tg plastic materials. Blow molding typically involves the injection molding of a preform in an injection mold, followed by pressurized-air inflation of this preform at a warm temperature in a blow mold. The bottle is then quenched below the Tg of the material by contact with the blow mold. This quenching after inflation, however, traps molecular orientation into the sidewalls of the bottle that can be released during boiling-water sterilization, causing the bottle to distort or shrink. In order to prevent shrinkage during boiling water sterilization, the Tg of plastics currently employed in the prior art to produce blow molded sports bottles is at least 30° C. above boiling water, that is, at least 130° C.
These high Tg materials also have certain deficiencies, such as cost, unfavorable consumer perception because of the presence of bisphenol A, insufficient chemical resistance, insufficient hydrolytic stability, etc, which can limit their use in these applications. Thus, there is a need in the industry for sports bottles produced from alternative plastic materials.